The present invention relates in general to the utilization of data found on legacy application screens, and particularly to a method and device for accessing data through the creation of maps of legacy applications.
Legacy applications (computer programs running on mainframe or host computers) are usually operated through standard terminal screen interfaces, such as the TN3270 screen protocol defined by IBM and others. While legacy applications remain useful today, their character based user interfaces are difficult to use when compared with today""s modern graphical user interfaces. Another problem occurs when the additional business logic needs to be added to the existing legacy applications. As a result, many programming hours are now spent updating the interfaces of legacy applications.
One way to update these interfaces is to create an application that allows the legacy application to run in an unchanged state, but allows the user to access the legacy application through a separate program operating on a personal computer or workstation. For these interfaces to work correctly, it is necessary to spoof the mainframe computer into providing the appropriate screens from which data can be extracted for the new interface. In this way, the mainframe application has no knowledge that the user is using a different front end. In addition, data entry must be allowed into the legacy application through the new interface.
In order to accomplish this, it is necessary to provide the new interface with knowledge about the terminal screens used by the legacy application. To do this, a xe2x80x9cmapxe2x80x9d must be created of the Legacy interface that sets forth how to access the data and input locations in the legacy application. Although prior art systems exist that are capable of developing these maps, the process by which these maps are created are clumsy. Typically, a map is created only with the help of a great deal of expert knowledge concerning the organization of the legacy application and with a great deal of time and effort on the part of the programmer. What is needed is an improved system that allows the creation of maps of legacy systems with a minimum of knowledge and expertise by the end-user.
The present invention meets this need by providing a simplified method and system for mapping legacy application data.
The mapping process consists of two phases: trail recording and mapping. In the trail recording phase, the user interacts with the legacy application using a terminal emulator built into the present invention. During such a session, trail recording can be turned on, which allows the present invention to record all of the user interaction with the legacy application.
The trail recording phase can be accomplished in a single session with the legacy application. In most cases, however, multiple sessions are used to access all areas of the legacy application in which data extraction or input is desired. Each of these sessions is saved in the system as a separate trail. Where multiple sessions are used, each trail is stored separately and later combined in the map of the legacy application.
The mapping phase begins after the trails have been collected. During this phase, the present invention analyzes the trails according to specific rules that are controlled by the end user. The primary goal of the mapping phase is to be able to identify each of the terminal screens used by the legacy application and all of the relevant data found on those screens. The map must also incorporate information on how the application moves from one screen to another.
The invention is able to recognize common screens and distinguish between separate screens by applying screen identification rules. Usually, no user intervention is required to create these rules, and the mapping phase can be accomplished automatically after the trails are generated. In some cases, however, the user will find it useful to rename the screens and fields with meaningful names. In addition, for those cases where the host application exhibits complex behavior or complex data layouts, it is possible for users modify the automatically created rules and to specify additional mapping rules.